# Meaning of Demand

The term demand is defined as the number of units of particular goods or service that consumer are willing to purchase during a specific period and under a given set of period.
Demand is distinct from desire and generally it is confused with desire. We can desire for anything. A mere desire for a commodity will not encourage a producer to produce unless it is backed by purchasing power. A desire can be transformed into demand only when,
o We have ability to pay i.e., income
o Willingness to pay
o It is possible to produce goods.
o Time period; and
o Price
Demand for a commodity is always expressed in relation to particular price, Place and time. This is so because with the change in place, time and price demand for a commodity may be different. Therefore the demand for a commodity is the quantity to be bought by a person at a particular price place and time. According to Benham, “The demand for anything, at a given price, is the amount of it which will be bought per unit of time at that price.”
Various economists give various definitions According to port. Bridge
“The term demand is defined as the number of units of particular goods or services that consumers are willing to purchase during a specific period and under a given set of conditions”

## Demand Function

The change in other factors cause change in demand because these factors cause shift in demand curse A demand faction also expressed as like.
Qx = Py Px, T,Y,P,E,A,B,……..)
Px = Price of ×commodity
T=Tastes of preferences,
Y= Income of the consumer
Q= quantity demanded of x commodity
E= Future price expectation
B= Income distribution in the economy,
Py = Price of related goods.
This relation gives the mathematical relationship bet the quantity demanded of a commodity and various determinant of demand.

# The Demand Function

The amount of a good that a customer is willing to buy and able to purchase over a period of time at a certain price, is known as the quantity demanded of that good. The quantity desires to be purchased may be different from the quantity of good actually bought by the consumer. As quantity demanded is a flow concept, the relevant time dimension has to be mentioned which will indicate the quantity demanded per unit of time. Demand is a relationship between the price and the quantity demanded, other things remaining constant. Hence the other things imply, the factors, which influence the decision of the consumer to buy.
If X1 denotes the quantity demanded and P1 its price per unit of the good, then other things remaining constant the demand function will be given as
X1 = f (P1)
The function shows that quantity demanded depends on the price. This means that any change in price will result in a corresponding change in the quantity demanded.
The change in the other factors cause change in demand because these factor cause shift in demand curve. A demand function also expressed as
Qx = F (PX, TP, y, PY, E, A, B………..)
PX = price of X commodity.
TP = Taste and preferences
y = Income of the consumer